桂北沙子江铀矿床赤铁矿地球化学特征及铀成矿启示  

Geochemical Characteristics of Hematite and Its Significance to the Uranium Mineralization in Shazijiang Uranium Deposit,Northern Guangxi Province

作　　者：赵子翔 陈琪[2] 王凯兴[1] 孙立强 刘晓东[1] 杨建俊 谭双 ZHAO Zixiang;CHEN Qi;WANG Kaixing;SUN Liqiang;LIU Xiaodong;YANG Jianjun;TAN Shuang(East China University of Technology,Nanchang,Jiangxi 330013,China;Research Institute No.230,CNNC,Changsha,Hunan 410000,China)

机构地区：[1]东华理工大学,江西南昌330013 [2]核工业二三〇研究所,湖南长沙410000

出　　处：《铀矿地质》2024年第6期1100-1117,共18页Uranium Geology

基　　金：国家自然科学基金面上项目(编号:42072095);江西省科技厅科技计划项目-对外科技合作计划(编号:20212BDH81006);中国核工业地质局高校科研攻关项目(编号:No.201619);东华理工大学研究生创新基金项目(编号:DHYC-202409)联合资助。

摘　　要：沙子江铀矿床是苗儿山铀矿田中具有经济价值的花岗岩型铀矿床,前人已对该矿床的成矿年代、成矿构造等进行了研究,而对蚀变矿物的研究较少。赤铁矿是沙子江铀矿床的重要蚀变矿物,与铀成矿关系密切。文章选取沙子江铀矿床成矿期赤铁矿为研究对象,在显微镜和扫描电镜(SEM)观察的基础上,阐明沙子江铀矿床成矿期赤铁矿的成因、成矿流体特征,探讨其与铀成矿之间的关联,以期为沙子江铀成矿作用提供新信息。研究结果表明:1)沙子江铀矿床成矿期赤铁矿是成矿前黄铁矿经热液作用与氧化的成矿流体发生氧化作用形成的;2)沙子江铀矿床成矿期赤铁矿形成时的流体为高氧逸度富Cl流体,可能以氧化的大气降水为主;3)大气降水与富CO_(2)的幔源流体混合形成的热液流体与豆乍山花岗岩相互作用,形成了富铀的氧化性流体,该流体与早期形成的黄铁矿相互作用,导致沉淀成矿并形成了赤铁矿。Located in the Miaoershan uranium ore field,Shazijiang uranium deposit is a granite-type one.The previous studies mainly focused on the ore-forming age and the structure,but few study was carried out on the alteration minerals.Hematite is a key alteration mineral intricately linked with uranium mineralization in the Shazijiang uranium deposit.This study employed microscopic and scanning electron microscope(SEM)observations to expound on the genesis,trace element characteristics,and ore-forming fluid properties of hematite formed in the mineralization phase in the Shazijiang uranium deposit.The objective is to elucidate its relation to uranium mineralization and understand the genesis of Shazijiang deposit.The results show that:1)The hematite in the ore-forming period was formed by the oxidation of the pre-ore-forming pyrite by oxidized ore-forming fluid in hydrothermal process.2)The fluid in the oreforming period was high oxygen fugatic-rich Cl fluid,which may be dominated by oxidized atmospheric precipitation.3)The hydrothermal fluid is the products of the interaction between atmospheric precipitation and CO_(2)-rich mantle source fluid,which mixed with the Douzhashan granite to generate a uranium-rich oxidizing fluid.This fluid subsequently interacted with early-formed pyrite,leading to uranium precipitation and the formation of hematite.

关 键 词：沙子江 赤铁矿 微量元素特征 铀成矿模式 

分 类 号：P619.14[天文地球—矿床学]